Concept explainers
A typical coal-fired power plant burns 300 metric tons of coal every hour to generate 2.7 × 106 MJ of electric energy, 1 metric ton = 1000 kg; 1 metric ton of coal has a volume of 1.5 m3. The heat of combustion of coal is 28 MJ/kg. Assume that all
a. Suppose the coal is piled up in a 10 m × 10 m room. How tall must the pile be to operate the plant for one day?
b. What is the power plant's efficiency?
Want to see the full answer?
Check out a sample textbook solutionChapter 11 Solutions
College Physics: A Strategic Approach (4th Edition)
Additional Science Textbook Solutions
Conceptual Integrated Science
Essential University Physics: Volume 1 (3rd Edition)
University Physics Volume 2
The Cosmic Perspective
Cosmic Perspective Fundamentals
Sears And Zemansky's University Physics With Modern Physics
- (a) How long will the energy in a 1470kJ (350kcal) cup of yogurt last in a woman doing work at the rate of 150 W with an efficiency of 20.0% (such as in leisurely climbing stairs)? (b) Does the time found in part (a) imply that it is easy to consume more food energy than you can reasonably expect to work off with exercise?arrow_forward(a) What is the average power consumption in watts of an appliance that uses 5.00 kW h of energy per day? (b) How many joules of energy does this appliance consume in a year?arrow_forward(a) Calculate the work done on a 1500-kg elevator car by its cable to lift it 40.0 m at constant speed, assuming friction averages 100 N. (b) What is the work done on the lift by the gravitational force in this process? (c) What is the total work done on the lift?arrow_forward
- A 500-W motor operates a Carnot refrigerator between 5 and 30 . (a) What is the amount of heat per second extracted from the inside of the refrigerator? (b)How much heat is exhausted to the outside air per second?arrow_forwardA power plant has been proposed that would make use of the temperature gradient in the ocean. The system is to operate between 20.0C (surface water temperature) and 5.00C (water temperature at a depth of about 1 km). (a) What is the maximum efficiency of such a system? (b) If the useful power output of the plant is 75.0 MW, how much energy is absorbed per hour? (c) In view of your answer to part (a), do you think such a system is worthwhile (considering that there is no charge for fuel)?arrow_forwardIn an air conditioner, 12.65 MJ of heat transfer occurs from a cold environment in 1.00 h. (a) What mass of ice melting would involve the same heat transfer? (b) How many hours of operation would be equivalent to mailing 900 kg of ice? (c) If ice costs 20 cents per kg, do you think the air conditioner could be operated more cheaply than by simply using ice? Describe in detail how you evaluate the relative costs.arrow_forward
- Over the course of a day, 4.0 kg of water evaporates from the leaves of a corn plant.a. How much energy is required to evaporate the water? (Assume that the temperature of the leaves is 30°C.)b. If the plant is active for 12 hours, how much power does this correspond to? You can think of this as the necessary power to drive transport in the plant.arrow_forwardA certain heat engine does 12.0 kJ of work and 8.50 kJ heat transfer occurs to the environment in a cyclical process. a. What was the heat transfer (in kJ) into this engine? b. What was the engine's efficiency (in percent)?arrow_forwardWind energy is becoming more common form of energy that can be used to run household appliances. a. If a windmill is connected to a hot water tank and is used to heat 60 L ( 60 kg) of water from 15 degrees celsius to 70 degrees celsius. How much energy is required? b. If energy from the utility company costs 0.35 cents per kilojoule, how much per kilojoule, how much money is saved in a year. If the water in the tank is heated 400 times?arrow_forward
- A 1100-kg car is backing out of a parking space at 5.2 m/s . The unobservant driver of a 1800-kg pickup truck is coasting through the parking lot at a speed of 3.2 m/s and runs straight into the rear bumper of the car. A. What is the change in internal energy of the two-vehicle system if the velocity of the pickup is 1.5 m/s backward after they collide? Express your answer with the appropriate units. Enter positive value if the energy increases and negative value if the energy decreases. B.What is the coefficient of restitution for this collision?arrow_forwardThe Bodø NATO base in northern Norway uses a heat pump to extract heat from ocean water. 7.0°C ocean water is continuously drawn into the system, heat is extracted, and the water is returned to the ocean at 3.0°C. When the system is working at full capacity, 2000 kW of heat is delivered to the building at the cost of 600 kW of electric energy.a. How much energy is removed from the water (the cold reservoir) each second?b. How much water moves through the system each second?arrow_forwardA geothermal heating system is installed outside a house by laying pipesunderground, as shown in the image.The heat is transferred from the ground to the pipes to keep the house warm. How does this system of heating the house reduce the impact on the natural environment?A by providing energy to the groundB by conserving underground energyC by using a sustainable source of energyD by transforming one form of energy to anotherarrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningPhysics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegeUniversity Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice University